Rotary switch

ABSTRACT

A rotary switch comprises a housing defining a first set of guide grooves wherein a set of spring-biased plungers are glidably mounted for operating a set of contact bridges. A cam disc is mounted in the housing for rotation about an axis. The plungers are biased into contact with the cam disc and rotation of the cam disc causes movement of selected ones of the contact bridges perpendicularly to the axis of rotation. A star wheel is mounted in the housing coaxially with the cam disc for rotation therewith and a set of spring-biased detent elements is glidably mounted in a second set of guide grooves defined in the housing for cooperation with the star wheel.

United States Patent 1191 Alsch Dec. 23, 1975 ROTARY SWITCH 2,892,0476/1959 Smith 200/153 LB x Inventor: Gottfried c Vienna, Austria3,566,051 2/1971 Hulterstrum 200/153 LB X [73] Assignee: Hubert Lauren'zNaimer,,Vienna, FOREIGN PATENTS OR APPLICATIONS Austria 1,517,882 3/1968France ZOO/153 LB 2] Filed: 9 1974 Primary ExaminerRobert K. Schaffer 1Appl No; 444,365 Assistant Examinerwilliam J. Smith Attorney, Agent, orFzrmKurt Kelman [30] Foreign Application Priority Data [57] I ABSTRACTFeb. 23, 1973 Austria 1627/73 A rotary switch Comprises a housingdefining a first Set 1 I of guide grooves wherein a set of spring-biasedplungg 1 ers are glidably mounted for operating a set of contact n e l el t u A [58] new of Search ZOO/153 tation about an axis. The plungersare biased into 17 18 contact with the cam disc and rotation of the camdisc 56 R f ed causes movement of selected ones of the contact brid- 1 eerences It ges perpendicularly to the axis of rotation. A star UNITEDSTATES PATENTS wheel is mounted in the housing coaxially with the2,030,890 2/1936 Oberhofiken 200/153 LB cam isc for rotation therewithand a set of spring- 2,245,369 6/1941 Smith 200/ 153 LB biased detentelements is glidably mounted in a sec- 2398307 4/ 1946 200/ 153 L3 X ondset of guide grooves defined in the housing for 00- 2,684,412 7/1954Bauer 200/153 LB x Operation with the Star WheeL 2,786,105 3/1957 Pawleyet al 200/153 LB X 2,823,285 2/1958 Stone 200/153 LB 3 Claims, 3 DrawingFigures US. Patent Dec. 23, 1975 3,928,740

ROTARY SWITCH The present invention relates to improvements in rotaryswitches.

Conventional rotary switches comprise a housing defining a set of guidegrooves and a set of springbiased plungers glidably mounted in the setof guide grooves. The plungers are operably associated with respectiveones of a set of contactbridges mounted in the housing and a cam disc ismounted in the housing for rotation about an axis. The plungers beingbiased into contact with the cam disc, rotation thereof causes movementof selected ones of the contact bridges perpendicularly to the axis ofrotation in response to the configuration of the camming surface of thecam disc. A rotary switch of this type requires detent means arranged tohold the cam disc in predetermined rest positions wherein no movement ofthe plungers is caused.

Usually, this detent means is constituted by a separate structural partwith its own housing connected to the switch housing proper by bolts ora bayonet coupling. This increases not only thecost of construction butalso the axial length of the switch unit.

It has also been proposed to mount the detent mechanism in the switchhousing and to use the cam disc of the switch also as a star wheelforming part of the detent mechanism. However, the usefulness of thisstructure is limited because the detents of the combined cam disc-starwheel also operate as camming surfaces causing movement of the plungersso that the desired operation of the switch is difficult to control.

It is the primary object of this invention to overcome thesedifficulties and disadvantages and to produce a rotary switch of thetype wherein the cam disc and detent mechanism are mounted in a singleswitch housing but the cam-controlled operation of the switch contactsis not impaired by the detent mechanism.

The above and other objects are accomplished in accordance with theinvention with a rotary switch which comprises a housing defining afirst set of guide grooves and a second set of guide grooves. A set ofcontact bridges is mounted in the housing and a set of spring-biasedplungers is mounted glidably in the first set of guide grooves and isoperably associated with respective ones of the contact bridges to movethem in response to the movement of the associated plungers. A cam discis mounted in the housing for rotation about an axis, the plungers beingbiased into contact with the cam disc and rotation of the cam disccausing movement of selected ones of the contact bridges perpendicularlyto the axis of rotation in response to the configuration of the cammingsurface of the cam disc. A star wheel is mounted in the housingcoaxially with the cam disc and coupled thereto for rotation therewithand a set of spring-biased detent elements is mounted in the second setof guide grooves for cooperation with the star wheel.

A rotary switch of this structure is particularly useful when the set ofcontact bridges consists of two diametrically opposed contact bridges,in which case the second set of guide grooves also consists of twodiametrically opposed guide grooves, and the axes of the plungers andthe two opposed guide grooves for the detent elements are angularlyspaced from each other by 90.

According to a preferred feature, the detent elements define boreshousing springs for biasing the detent elements, and mating guide orretaining means hold the preferred embodiment thereof, taken inconjunction with the accompanying drawing wherein FIG. 1 is a top viewof the switch mechanism, showing the interior of the switch housing,with the cover removed;

FIG. 2 is a bottom view showingthe detent mechanism; and

FIG. 3 shows a sectional view along line IIIIII of FIG. 2.

Referring now to the drawing, the illustrated rotary switch compriseshousing part 1 and cam disc 2 mounted centrally therein for rotationabout an axis, the axis of rotation being defined by a shaft (not shown)to which the cam disc is keyed by teeth 3. The cam disc of the switchmay also be coupled to a like or similar rotary switch mounted axiallyadjacent thereto.

Housing 1 defines a first set of two radially extending, diametricallyopposed guide grooves 4 wherein plungers 5 are glidably mounted, eachplunger being operably associated with a respective one of contactbridges 6. In the illustrated embodiment, the plungers carry the contactbridges for movement therewith. Compression springs 7 bias the plungersinwardly into contact with cam disc 2 and rotation of the cam disccauses movement of a selected one of the contact bridges perpendicularlyto the axis of rotation in response to the configuration of the cammingsurface of the cam disc, as clearly shown in FIG. 1. Switch contacts 8are mounted in grooves in the switch housing for cooperation with thecontact bridges so that movement of the selected contact bridge closes aselected switch contact. The contact terminals are shown at 10. All ofthis structure is substantially conventional.

In accordance with this invention, the housing defines a second set ofguide grooves 11 and 12, the diametrically opposed, radially extendingguide grooves 11 and 12 being angularly spaced from the axes of plungers5 to Detent elements 13 are glidably mounted in grooves 11 and 12 forcooperation with star wheel 14 (see FIG. 2). The star wheel is mountedin the housing coaxially with cam disc 2 and axially adjacent thereto,the cam disc and star wheel being coupled together for common rotationand forming a single structural unit. If desired, the cam disc and starwheel may be integral with each other.

The structure of the detent elements is best shown in FIGS. 2 and 3. Asillustrated, each detent element 13 is a slide having a pair of lateralguide grooves 15 cooperating with a mating pair of guide rails 16 in theside walls of guide grooves l1, 12 so as to hold the detent elements intheir guide grooves against movement outwardly of their guide grooves inthe direction of the axis of rotation (see arrow A in FIG. 3). Also, thedetent elements define cylindrical bores 17 housing springs 18 forbiasing the detent elements against the star wheel. The ends ofcompression springs 18 abut against the bottoms of the guide grooves ll,12 and bores 17, respectively, as best shown in FIG. 2.

ln assembling the rotary switch, spring-biased detent elements 13 arefirst inserted into their guide grooves 11, 12 through the center recess21 of housing part 1, whereupon the cam disc-star wheel unit is mountedin 3 the center recess. Plungers 5 may now be mounted in their guidegrooves 4 to complete the assembly.

It will be obvious from the above description that a rotary switch ofthe described structure is not only compact by providing a singlestructural unit of cam disc and detent mechanism while assuringindependent operation of the cam disc and the detent mechanism but, atthe same time, meets all operational requirements for such switches.Furthermore, the axial length of the switch is reduced, thus savingmaterial and space.

It will be useful to make all of the switch parts, including the housingpart 1, the cover (not shown), the cam disc and the star wheel byinjection molding a thermoplastic synthetic resin, except, of course,the parts which must be electrically conductive and the springs.

What is claimed is:

1. A rotary switch having an axis of rotation and comprising:

a. a housing defining a plurality of first radial guide grooves and asecond radial guide groove axially adjacent said first guide grooves andangularly spaced from each of said first grooves;

b. a plunger radially movable in each of said first grooves;

c. a cam disc mounted in said housing for rotation about said axis andhaving a cam face opposite said first grooves;

(ill

d. first yieldably resilient means biasing each plunger towardengagement with cam face;

e. a star wheel secured to said cam disc for joint rotation about saidaxis;

f. a detent element radially movable in said second groove;

g. second yieldably resilient means biasing said detent element towardengagement with said star wheel; and

h. a plurality of contact bridges mounted in said housing andoperatively connected to respective ones of said plungers for operationwhen the connected plungers are moved during rotation of said cam discagainst the biasing of said first yieldably resilient means.

2. The switch of claim 1, wherein said first grooves are equiangularlydistributed about said axis, said second groove bi-secting the anglebetween two adjacent first grooves.

3. The switch of claim 1, wherein said housing defines an additional,second, radial guide groove angularly spaced from each of said firstguide grooves, the switch including additional detent element radiallymovable in said additional second groove, and additional yieldablyresilient means biasing said additional detent element toward engagementwith said star

1. A rotary switch having an axis of rotation and comprising: a. ahousing defining a plurality of first radial guide grooves and a secondradial guide groove axially adjacent said first guide grooves andangularly spaced from each of said first grooves; b. a plunger radiallymovable in each of said first grooves; c. a cam disc mounted in saidhousing for rotation about said axis and having a cam face opposite saidfirst grooves; d. first yieldably resilient means biasing each plungertoward engagement with cam face; e. a star wheel secured to said camdisc for joint rotation about said axis; f. a detent element radiallymovable in said second groove; g. second yieldably resilient meansbiasing said detent element toward engagement with said star wheel; andh. a plurality of contact bridges mounted in said housing andoperatively connected to respective ones of said plungers for operationwhen the connected plungers are moved during rotation of said cam discagainst the biasing of said first yieldably resilient means.
 2. Theswitch of claim 1, wherein said first grooves are equiangularlydistributed about said axis, said second groove bi-secting the anglebetween two adjacent first grooves.
 3. The switch of claim 1, whereinsaid housing defines an additional, second, radial guide grooveangularly spaced from each of said first guide grooves, the switchincluding additional detent element radially movable in said additionalsecond groove, and additional yieldably resilient means biasing saidadditional detent element toward engagement with said star wheel.